<template>
  <div>
    <!-- show-file-list: 是否显示上传的文件列表
           action: '#' 用来指定文件要上传的地址,由于我们需要定制上传动作(这里设为#)
        :http-request: 自定义上传行为(重点)
        on-success: 上传成功之后的回调
        before-upload: 上传之前的检查
        :on-success="handleAvatarSuccess"
      -->
    <el-upload
      class="avatar-uploader"
      action="#"
      :show-file-list="false"
      :on-success="handleAvatarSuccess"
      :before-upload="beforeAvatarUpload"
      :http-request="upload"
    >
      <img v-if="imageUrl" :src="imageUrl" class="avatar">
      <i v-else class="el-icon-plus avatar-uploader-icon" />
    </el-upload>
  </div>
</template>

<script>
export default {
  data() {
    return {
      imageUrl: ''
    }
  },
  methods: {
    upload(file) {
      console.log(file)
    },
    handleAvatarSuccess(res, file) {
      this.imageUrl = URL.createObjectURL(file.raw)
    },
    beforeAvatarUpload(file) {
      const isPNG = file.type === 'image/png'
      const isLt2M = file.size / 1024 / 1024 < 2
      if (!isPNG) {
        this.$message.error('上传头像图片只能是 PNG 格式!')
      }
      if (!isLt2M) {
        this.$message.error('上传头像图片大小不能超过 2MB!')
      }
      return isPNG && isLt2M
    }
  }
}
</script>

<style>
.avatar-uploader .el-upload {
  border: 1px dashed #d9d9d9;
  border-radius: 6px;
  cursor: pointer;
  position: relative;
  overflow: hidden;
}
.avatar-uploader .el-upload:hover {
  border-color: #409eff;
}
.avatar-uploader-icon {
  font-size: 28px;
  color: #8c939d;
  width: 178px;
  height: 178px;
  line-height: 178px;
  text-align: center;
}
.avatar {
  width: 178px;
  height: 178px;
  display: block;
}
</style>
